Technical Cable for battery

Choice for me depends on the situation and battery voltage and location. 4 gauge for larger engines if the 12V battery is close to the starter, 4/0 gauge for 6V battery in the same situation. Battery not close welding cable for 12V or 6V. 6 gauge for small engines with a close battery. When I had my diesel pickup, my jumper cables were welding cable with heavy duty clamps. Still use those.

 

No argument here. I have a trunk mounted battery in the Cyclone, the positive cable runs through RH rocker panel ( in a protective sheath) to the starter. The ground cable goes to a welded on lug in the trunk then runs through the LH rocker panel ( in a protective sheath)to another frame mounted lug, then to the engine. I use serrated washers on everything. Absolutely no issues with slow cranking or dim lights at idle. I run a 125amp alternator, and have a mega fuse on the front frame rail between the started and the alternator.

 

The ground cable is much more important. Here's mine on delivery day

 

I use welding cable that I bought at Lowes, I usually mount the battery in or near the back of the car so I need longer cable than is available at the automotive parts house. HRP

 

Welding cable has much finer strands to allow better flexibility which also increases it's density and thus better ampacity than typical battery cables. A welding cable of equal size like say 1/0 will have double the ampacity of the usual cheap auto parts store battery cables of the same size.
A 1/0 welding cable is rated 300 amps, where the same 1/0 battery cable bought at the parts store is rated half that. I use nothing but welding cable for all my battery leads, and ground cables to the block.

 

Man, the first liar on this thread doesn't have a chance with you around

 

I run my trunk mounted battery ground straight to frame, then ground the engine/body to frame.
I've never had an issue in the many years of starting my higher compression engines or any electronics in the car.

Those of you not looking into Battery Cable USA as a source to get your cable are missing out, they also sell welding cable, marine cable and smaller wire.

 

Well, we ground this topic to death, tired of talking about out of balance wheels, put the brakes to the DOT3 post and exhausted the pipe thread all in one week, what other world problem can we solve? The G Seven could learn a lot from the HAMB.

 

There must be something I don't understand about how inflation is calculated..........I'm sure they said we only had about 6% inflation. (interpret that as sarcasm) I'm buying some wire to hook up an emergency generator. Think I'm gonna have to remortgage my house. I did hear that the gov is going to stop making pennies because it costs more to make them than their face value.

 

Another thing to watch out for in cheaper pre-made cables is end connections that are made of copper plated steel.

In the same vein, common jumper cables have been made for years now with steel clamps and tiny copper inserts that actually bite onto the battery terminals. Now those little inserts are also merely plated steel.

Caveat Emptor!

 

Sorry, that's just not true along with the 'skin effect' that usually comes up. If equal size copper wire and made to American Wire Gauge specs, there's no difference. Using 4/0 wire as an example, it has a conductor cross-sectional area of 212,000 circular mils and a resistance of .049 Ohm per thousand feet. Same size + same resistance = same performance. Where the trouble comes in is who/how its rated. Automotive battery cables, who knows how those are rated as it's an unregulated application. The National Electrical Code has its own rating based on continuous duty and meeting certain temperature restrictions as to insulation and terminations as well as allowable voltage drop. But welding has its own rating system, operates at lower voltages, and is non-continuous service what with delays to change rods and welder duty cycles. Your comparing apples and oranges...

Because our vehicle wiring operates on a mere 12V, voltage drop is a big deal. It's not dependent on system voltage, it's strictly a load current/resistance calculation. A circuit with a 6V drop would be a disaster in a 12V circuit, within allowable specs in a 120V system, and not even worth noticing in a 1200V system. There's only two ways to reduce drop; shorten the wire path (less wire) or bigger wire.

 

Huge and stranded is best.

 

battery cables yes , hitchhiker chicks no

 

Welding cable will have typically have an EPDM insulation, which assists its greater flexibility. However, EPDM has unsatisfactory resistance to substances such as gasoline, motor oil, and grease which can cause to degrade and turn mushy - despite as advertised. It is also has lower abrasion resistance.

Battery cable will have a PVC (SGT cable) or cross-linked polyethylene (SGX cable) insulation. Both of these will have better resistance to automotive chemicals and abrasion.

At my employer, we're switching away from using the EPDM insulated cable on the machinery we manufacture in favor of the SGT/SGX cable. We've been finding older machines with degraded EPDM cables, which can result in potentially hazardous situations. YMMV depending upon how oily your undercarriage gets.

 

I totally disagree. Cables depend on density of strands, so circular mills of a cable of for instance 1/0 with maybe 16 strands vs. welding cable with thousands of strands is much higher for the fine strand cable and thus higher current rating. Check any source for standard wiring amperage vs. welding cable amperage. It's not that hard to look at the charts and see. Welding cable doesn't operate at 12v. so it's completely fair to compare it to other cables at the same amperage. If your theory was true then you'd rate one solid 1/0 wire the same as multi strand 1/0 wire, and that's not true. Charts show that even with small gauge wire like 12awg that stranded is lower amperage than solid 12awg. It may not change commercial wiring ampacities for breaker ratings, but the current carrying capacity of solid vs. stranded is certainly different. As is ampacity of finer strand wire vs. coarse strand wire.
As for the voltage drop, a big car might have 12 ft. of cable from battery to starter and you're not going to see any voltage drop in 12 ft. with this size cable, even at 12vdc. So comparing voltage drop for small conductors at 120 v. vs. large conductors at 12v. just doesn't relate. Like apples and oranges.
I've had trunk mounted batteries for every car I've built for decades and run either 1/0 or 2/0 welding cable, and never an issue starting some very high compression engines in any of them.
And a starter draw is more like a welder operation in it isn't a constant draw. It's occasional, and rarely a continuous operation. Don't confuse smaller 6v or 12v loads on cars with starter in rush for short term that's more like striking an arc with a welder.

 

Thanks Steve,
Dan

 

American wire gauge is the US standard for sizing wire by conductor cross section. Where multiple stands are used, it's the total of all strands added together. What you're saying is welding cable is somehow 'bigger' than other types because its 'denser'. There are no engineering specs to support that. Again, let's look at an example...

A 4/0 building wire has a nominal conductor cross section area in circular mils of 212,000. These typically use 19 strands, so that number divided by 19 gives you 11157.89 cm per strand. This is slightly larger than a #10 wire. The nominal OD is .46". They also make 'compact conductor' wire where the strands are pressed into a hexagonal shape to eliminate roughly 90% of the space between them for a roughly 10% reduction in overall conductor diameter, although these are only available in aluminum. There can be variations between different manufacturers, but all will be pretty close to these numbers.

And the welding cable? If it's listed as a 4/0, it needs to be at least within shouting distance of 212,000 cm. To carry more current, it should be higher. This manufacturer doesn't give total conductor area (or resistance per 1000 feet) but does give a strand count of 2029 strands of #30 wire. Welding Cable Spec Sheet
Number 30 wire has a circular mil area of 101, so multiplying that by 2029 gives up 204,929 total cross sectional area. Rounding up will get you to 4/0. That is less than a 'regular' 4/0 cable. As to it being 'denser', nominal OD swells from .46" to .75", an increase of over 60%. That makes sense, because if it were tightly packed it would be much harder to bend.

Note that they also tell you point-blank NOT to use the welding amperage tables if using it in a 600V in-line application, which we are. And before you howl that our 12V systems don't operate at 600V, remember that the NEC classifies almost ALL wire between 0 and 600V under the same 600V spec. Over 600V opens up a whole 'nother can of worms as you've entered the realm of 'high voltage'. Their rating for your 1/0 cable is 190 amps.

Now, I'm not going to tell you that you have the 'wrong' wire size. If it's working, it's good. But that doesn't mean I'd recommend that size to everyone. A 'typical' V8 starter draws 250 amps, but that number can swing by over 50 amps in either direction depending on multiple factors. You can impress any current on any wire, with results varying from nothing to the wire getting warm, all the way to vaporizing in an explosion. And EVERY circuit has voltage drop, just how much is again dependent on multiple factors.

 

And I'll throw this out here for your consideration... Aluminum building wire. Lighter, cheaper and easier 'worked' compared to copper building wire. One downside is to get the same amperage rating you need a bigger wire. For example, to duplicate 4/0 copper wire you'll need to jump up to 350 mcm cable. Weight is only .4 lbs per foot, 4/0 copper is .75. Price, the aluminum is $4.30 per foot, considerably less than welding cable. Yes, it will still be harder to work compared to welding cable as it doesn't bend as sharply but not horribly so and it will need to be properly secured with insulated clamps. You'll also need crimp-on terminal lugs (don't even think about screw lugs) and take care not to nick the strands when stripping. Seal the terminal with industrial shrink tube. But it is doable, I've done this way in the past.

 

I believe these are the " screw lugs" you're referring to ? These are listed as being appropriate for both aluminum & copper wire ...

 

... but they don't like vibration...

 

That applies to most mechanical fasteners ..

 

You might get away with copper and aluminum in a controlled environment, but out in the open, you're going to get a galvanic reaction. Copper corrodes aluminum. The following chart tells you which metals play nice and which don't.

 

there is, but they use high-flex battery cable.

 

Where is your sense of adventure?

 

You're putting words in my mouth and making assumptions Steve. I never stated that welding cable is larger for equal rating sizes. It is indeed denser with it's fine strands and does indeed carry higher current flow with the density of those fine strands.
As you likely know every conductor has a rating based on whether it's continuous or intermittent, and the intermittent or short cycle always is higher. Likewise every conductor has a failure point rating, and even tiny wires like 12awg are rated over 1000 amps before they melt down.
You keep "howling" and I'll keep using welding cable for my main battery leads. Post whatever works for you, but I'll stick with experience and real world scenarios that have shown me it simply works, and has worked for me for decades.

 

Look at the chart above that @alanp561 posted ! Nickel chrome likes everybody!!

...

 

why do you hate Jungle Pam?

 

It's a great idea. I was fortunate that I got a nice box of 2/0 welding cable long ago. Used it full length in my racer. 14:1 compression. Used a stock starter with a proper rear brace and it's own ground from a starter bolt to the frame. No issues. I still have some. Use it on restoration stuff since 6V is very amp sensitive and of course higher amp loads. I don't solder them any more. I make or buy proper ends and I stake them on and cover with shrink tube. No worries about the solder flux slowly degrading the connector.

 

When you solder for electrical you use rozen flux , generally considered non- corrosive , hence the reason it's used . Acid flux has other purposes .

 

ever hear of penatrox ? There are similar products under similar brand names to prevent corrosion . The original reference was using aluminum screw type connections on aluminum cable .